On the pharmaceutical market in general and especially in the dermic, ophthalmic, oral and nasal sectors, there are multiple products, such as certain eye drops, whose shelf life, once all of the ingredients have been mixed, in most cases does not exceed four weeks.
In view of these circumstances, for some time now the ingredients of the product are grouped in two parts that are packaged separately and independently.
Generally, one of the parts is in a powdered lyophilized form, while the other one is in a liquid state. Each one of the parts maintains individually its stability during the proposed period of validity. The end user himself is the one who must mix both parts when the product is to be administered. The stability of the reconstituted product suffices to guarantee the indicated time of use.
European Patent No. 344,849 and European Patent No. 217,425 provide attempted solutions to this problem.
European Patent No. 217,425 is directed towards a device of this type, in which the mouth of the container has a thread upon which the cap, which is provided with a seal, is retained. Likewise, a cup is pressed on the mouth, inside of which the tubular sleeve is housed. The tubular sleeve terminates at its top edge with a discoidal wing and continues in a truncated-cone shaped portion to carry out the functions of a medicine dropper.
In this patent, after removing the seal from the cap, the cap can be screwed down. The movement of the cap pushes the tubular sleeve, which presses against the bottom of the cup, carrying out the breaking thereof and producing the mixing of both products.
This patent presents the problem that after removing the seal to effect the breaking of the bottom it is necessary to exert a certain effort; at the same time to permit the application of the mixed product it is necessary to press the container. During this pressing step, the discharge of the cup and/or of the tubular sleeve frequently occurs. Thus, all of the product is inadvertently dispensed. This is a serious problem because the correct amount of the product has not been dispensed. This patent also fails to disclose the use of seals, which prevents the use of this patent for mixing of two liquids. This patent also fails to accommodate for the invulnerability of the container, nor for a mechanism that permits the dose to be repeated (fox example, a drop), nor is the versatility of filling and final conditioning of the container set forth.
Concerning European Patent No. 344,84, this patent is directed to a device, in which the cup has an outside coaxial flap that includes an annular rib protruding radially inwardly. The rib retains the cup on the edge of the mouth of the container in such a way that it prevents, when application takes place, the cup from being removed. This feature however, is not necessary in this model given that it does not act as a medicine dropper, because the application of the mixed product is done entirely during treatment. In this patent, the breaking of the bottom is done by pressing the cap and not screwing it, as in the prior patent. Breaking the bottom by pressing creates greater difficultly for breaking the bottom of the cup given that the force to be exerted is much greater. Further, in this patent, the cylindric sleeve may be removed by effecting the application.